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51.
A series of column studies, with aquifer material from the former Nebraska Ordinance Plant (NOP), were performed to explore the phenomenon of electron competition from ubiquitous inorganic electron acceptors (nitrate and sulfate) present in contaminated groundwater. Acetate was used as a source of readily biodegradable carbon in all of the treatment‐column systems. Influent hexahydro‐1, 3, 5‐trinitro‐1, 3, 5‐triazine (RDX) concentrations (1–1.8 mg dm?3) were completely removed to below detection levels of 20 µg dm?3 in all treatment‐column systems without any nitroso‐metabolites. In the control‐column system (with no carbon amendment) significant levels (~30% of the inlet molar RDX) of nitroso‐substituted RDX derivates were observed in the effluent stream. The estimated first‐order biodegradation rate coefficient for RDX was highest (0.79 h?1) in the treatment‐column system where acetate was the only amendment, about 52 times higher than the rate coefficient (0.015 h?1) obtained in the control‐column system. The presence of sulfate (100 mg dm?3) in influent groundwater temporarily delayed the onset of RDX biotransformation without any adverse effects on overall RDX biotransformation. Coexistence of low (100 mg dm?3) nitrate levels in the influent feed water reduced the first‐order biodegradation rate coefficient obtained in the absence of nitrate by about 80% to 0.16 h?1. These nitrate levels, however, were low to halt the RDX biodegradation probably because the available carbon levels were high enough to exceed the demands for nitrate reduction. High levels of nitrate (500 mg dm?3) initially halted RDX removal, and significantly reduced the rate of RDX biotransformation by about 98% to 0.02 h?1, thereby increasing the half‐life from 0.9 h in the absence of nitrate to about 32 h, with noticeable levels of untreated RDX in the effluent stream. Contrary to the expectations, the presence of ammonium in conjunction with acetate resulted in a lower (0.09 h?1) biodegradation rate coefficient as compared with the one obtained in the absence of ammonium. Copyright © 2003 Society of Chemical Industry  相似文献   
52.
Effects from chlorination and dechlorination of Savannah River water were studied during the development of biofouling countermeasures for a proposed cooling tower system required for thermal mitigation of nuclear reactor cooling water effluent. Testing was conducted to assess chlorine demand and dissipation rates as well as the environmental acceptability of using sodium sulfite as a dechlorinating agent. Chlorine demand varied significantly, but in an unpredictable manner during seven seasonal sampling dates. A chlorine dosage of 3–5 mg/l was generally adequate to provide a free chlorine residual of 1 mg/l. Static 48-h bioassays with bluegill showed no acute toxicity for chlorinated/dechlorinated cooling water containing up to 64 times the calculated stoichiometric concentration of sodium sulfite required for dechlorination. Experiments measuring the depletion of dissolved oxygen and flow-through (96-h) bioassays with bluegill and largemouth bass further substantiated the environmental acceptability of using sodium sulfite as a dechlorinating agent.  相似文献   
53.
脱氯剂的工业应用   总被引:2,自引:0,他引:2  
应用脱氯剂是解决炼油二次加工装置氯腐蚀问题的最有效措施之一。对脱氯剂工业应用中的一系列问题进行了探讨与剖析,尤其对脱氯剂自燃的原因进行了分析并提出了相应的预防措施。  相似文献   
54.
催化重整装置的氯化铵结盐与腐蚀问题   总被引:5,自引:0,他引:5  
由于胜利原油加工量的增加 ,致使催化重整装置原料油中氯含量大幅度上升 (设计值为 10 μg/g ,最高达 74 μg/g) ,因而造成氯化铵结盐并多次发生腐蚀泄漏事故。分析认为 :预加氢进料含水从而造成H2 S -HCl-H2 O腐蚀环境和铵盐水解是造成系统腐蚀的主要原因。与此同时 ,提出了增设并列脱氯罐及提高设备材质等建议。  相似文献   
55.
In this study, we followed up, by measuring the reductive desorption patterns, the time-dependent growth of the self-assembled monolayer (SAM) of a thiol compound (typically cysteine) formed on polycrystalline Au (poly-Au) electrode. Cysteine molecules appeared to adsorb preferentially and consecutively at the Au(1 1 0), Au(1 0 0) and then at the Au(1 1 1) surface domains of the poly-Au. A 95% surface coverage of cysteine (Γcysteine) was attained after 5 s, 120 s and more than 300 s for the Au(1 1 0), Au(1 0 0) and Au(1 1 1) domains, respectively, of the poly-Au electrode. The electrochemical reduction of molecular oxygen (O2) in O2-saturated 0.5 M KOH was utilized as a probing reaction for the extent of the compactness of the SAM. A binary SAM of two thiols (cysteine and cystamine) has been successfully designed over the poly-Au electrode at which a precise positioning of cysteine was achieved, i.e., cysteine was attached to the Au(1 1 1) domains, while cystamine to the Au(1 0 0) and Au(1 1 0) domains. SEM images for the electrodeposited Ag over the cysteine sub-SAM/Au electrode gave a possible mapping of the Au(1 1 1) domains of the poly-Au electrode.  相似文献   
56.
中国石油化工股份有限公司齐鲁分公司胜利炼油厂600kt/a连续重整装置预处理系统为全馏分加氢的工艺流程。为了增加对原料的适应能力,增上了脱氯反应器(原料氯含量的设计值为7μg/g)。预处理系统的原料主要由第一、二常减压蒸馏装置的常顶石脑油、部分乙烯抽提油及外购石脑油组成,石脑油经加氢反应后,由脱氯反应器脱除反应生成的HCl,在蒸发脱水塔脱水、脱硫化氢,在预分馏塔切除C6以下的组分(即拔头油),为重整催化剂提供合格的原料。装置开工运转7个月后预处理系统首次出现铵盐堵塞现象,12个月后设备开始出现腐蚀泄漏情况。针对装置的腐蚀状况,采取了水洗及增加副线等措施,同时提出了根本解决顸处理系统腐蚀问题的建议。  相似文献   
57.
郭新忠 《中国氯碱》2014,(12):9-10,31
介绍了离了膜电解槽装置各部分对盐酸的使用标准、品质的要求、使用盐酸的原理等不同要求及电解工序对盐酸的使用情况。  相似文献   
58.
This paper describes two efficient strategies to suppress β‐H elimination during the palladium/copper bimetallic system‐mediated cross‐coupling between alkynamides and alkenes. Remote donor groups with the terminal olefins, such as toluenesulfonamide, phosphate, sulfone, etc., cooperate with the amide of alkynamides and chelate the palladium active center, to promote C(sp3) O bond formation by suppressing the β‐H elimination. Another strategy uses the rigid structure of norbornene to make an intermediate without a syn‐β‐hydrogen to achieve reductive elimination of the C Cl bond.

  相似文献   

59.
对沉铁渣还原熔炼—高温烟化过程的渣型进行研究。结果表明,沉铁渣的熔点介于1 100~1 200℃,且在CaO/SiO2=0.75、1≤Fe2O3/SiO2≤10和1 250℃的条件下,沉铁渣的黏度为0.6~0.7Pa·s,流动性较好,铅锌挥发率较高(96%),可以满足烟化炉作业对炉渣性能的要求。  相似文献   
60.
《石油化工》2015,44(4):477
以具有较大比表面积的ZSM-5分子筛和γ-Al2O3为载体,利用等体积浸渍法将活性组分Cu O和Mg O分别负载在载体上,制得Cu O/ZSM-5,Mg O/ZSM-5,Cu O/γ-Al2O3,Mg O/γ-Al2O34种吸附剂;采用低温N2吸附-脱附和XRD等方法对吸附剂Cu O/γ-Al2O3和载体γ-Al2O3的结构进行了表征;考察了4种吸附剂对直馏石脑油中氯化物的脱除效果,并得到了最佳吸附条件。表征结果显示,当γ-Al2O3负载活性组分Cu O后,孔体积和平均孔径均增大,且Cu O均匀负载在载体上,增加了吸附剂的吸附能力。实验结果表明,脱氯效果最好的吸附剂是Cu O/γ-Al2O3,当Cu O负载量为12%(w)时,在吸附温度20℃、吸附剂与直馏石脑油的质量比为1∶15、吸附时间20 min的最佳吸附条件下,Cu O/γ-Al2O3的吸附效果最佳,对氯化物的脱除率达59.93%。  相似文献   
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